John All has survived encounters with black mamba snakes, run-ins with wild jungle animals, and a brush with death in an icy tomb. No one knows the outer limits of our changing planet quite like him. In May 2014, the mountaineer and scientist John All plunged into a crevasse in the Himalayas, a fall that all but killed him. He recorded a series of dramatic videos as he struggled to climb seven stories back up to the surface with a severely dislocated...